A network switch may exchange data between multiple interfaces that run the same or different protocols: An interface is a physical module in a network switch which connects to customer premises equipment (CPE) or a network trunk, and runs a specific service or network protocol toward the customer side or network side.
FIG. 1A is a network diagram illustrating a service provider's wide-area ATM network 100 providing end-to-end services between customer premises equipment (CPE) or customer networks. The interfaces connecting the edge switches in a service provider's network and CPEs or customer networks define the service demarcation points between customers and the service provider. It is the service provider network's responsibility to interconnect two service demarcation points, or service endpoints, to allow communication between customer's different locations. As shown in FIG. 1A, network edge switches 120, 122, 124, and 126 are each connected to an ATM/PNNI network 130. Switch 120 is connected to a customer ATM network 132 and switch 122 is connected to a customer ATM CPE 134. Switch 124 is connected to a metro Ethernet network 136 and Frame Relay network 138. Switch 126 is connected to Ethernet network 140, MPLS network 141, and Frame Relay CPE 142.
The service endpoints in switch 120 and switch 122 can communicate with each other via standards-based PNNI signaling and routing protocols. For example, for an ATM service endpoint in ATM network 132 to communicate with ATM CPE 134, the ATM service endpoint in ATM network 132 sends PNNI standards-based signaling messages to set up a virtual circuit between the ATM service endpoint in ATM network 132 and the ATM service endpoint in ATM CPE 134.
The service endpoints in switch 120 and switch 126 may not be able to communicate with each other because there is no standards based protocol for signaling and routing between service endpoints running different protocols. Note that the service endpoint in switch 120 is ATM, but the service endpoint in switch 126 is either Frame Relay or Ethernet. These may only be possible if switch 120 and switch 126 are from the same manufacturer, so they may develop some proprietary method of signaling between service endpoints with different protocol types. For example, for an ATM service endpoint in ATM network 132 to communicate with an Ethernet service endpoint in Ethernet network 140, proprietary information may be included in a proprietary header in each packet sent to switch 126
FIG. 1B is a packet format illustrating an ATM packet 150 with proprietary information carried in the packet header. Specifically, packet 150 includes standard ATM header information (152, 154, and 158) and proprietary information 162 to indicate, e.g., the real type of service endpoints. Packet 150 is an example of a packet with proprietary information that may be sent from an ATM service endpoint in ATM network 132 to an Ethernet service endpoint in Ethernet network 140. Switch 126 uses proprietary information 162 to determine to which interface to send the packet for forwarding. The challenge of using proprietary header information or a proprietary encryption method is it requires that the edge switches that communicate with each other share the same proprietary method to connect different types of service endpoints. In general, this means that participating edge switches must agree and understand the proprietary method beforehand, which most likely requires the two edge switches come from the same manufacturer, putting a significant constraint on service providers for introducing new edge switches to meet the need of network growth and expansion. There is a need to allow an edge switch to be inserted into an existing network running standard based signaling/routing protocols, to communicate between the service endpoints on existing edge switches and new service endpoints on the new edge switch which may not be recognizable by the standard signaling/routing protocols. For service providers, this would allow them to introduce new products into its existing network for new service deployment with minimum disruption. For switch vendors, it would also be beneficial to maintain a generic, common service interface in an edge switch, adaptive to the type of networking protocols running in the network the edge switch is connected to, to represent real service endpoints for signaling/routing over the network. This allows common software developed in the edge switch to connect to multiple networks running different networking protocols.